During our research we discovered a number of low-level Bluetooth issues on mobile phones. We details those here plus the workarounds that work or do not work.
The older the mobile phone hardware the worse its performance. No surprises there. There are certain devices, or pairings of devices, that cause issues. These are detailed in this section.
There are a number of ways Operating Systems behave or bugs that are in how certain versions of those Operating Systems operate. The main one hampering Bluetooth based contract tracing apps is the ‘Apple device not discovering other Apple devices in the background’ bug within iOS. This and other issues are detailed in this section.
The bigger the croud, the louder the talk. No difference with radio based protocols like Bluetooth. We detail issues we found and workaround and approaches to minimise interference and cross talk here. We generally call this issue Crowding as shorthand.
Whilst not directly the subject of our research we have some insight in to Distance Estimation Calibration and so include this information here.